30 Part IIL—Twenty-sixth Annual Report 
were still alive when observed, and appeared to be endeavouring to leave 
the fish, and making their exit by the mouth. _ In this species the head is 
comparatively small and compressed and provided with two nearly circular 
suckers placed opposite each other on the flattened sides, as shown in the 
drawing (Plate V,, fig 5). Each of the suckers measure about 5 mm. in 
diameter, and they are surmounted by aslightly projecting ledge armed 
on the under side with numerous minute hook-like denticles. 
One incomplete specimen measured about 26 inches in length, and 
another about half that length, (Pl. VL., fig. 2). According to Diesing, 
this Cestode may attain a length of six feet. It has been recorded by 
Rudolphi from Orthagoriscus mola, captured in the Mediterranean. 
Prof. Linton also records this species, and mentions one of the specimens 
as being 150 centimetres long (nearly sixty inches). Van Beneden 
records the same worm from the coast of Belgium, and states that he 
has seen a score of individuals in a single fish,* while Malard also 
records it from the coast of La Manche, and apparently all from the 
same species of Sunfish. 
Genus Schistocephalus, Creplin (1829). 
Schistocephalus solidus (O. F. Miiller). Pl. VII, figs. 7-8. 
1776. Tenia solida, O. F. Miiller, Zool. Danicee Prodromus, 
pp. 26-37. 
1808. Bothriocephalus solidus, Rud., Entozoorum, Hist. Nat., 
20. ee 
1829. Schistocephalus dimorphus, Crep., Nov. obs. de Entoz.,. 
95 
18507 Schistocephalus dimorphus, Dies., Syst. Helminth., 
vol. i., p. 584. i 
1893. Schistocephalus dimorphus, Olsson, Bidrag till Skand 
Helminth fauna, ii, p. 15. 
1896. Schistocephalus solidus, F. W. Gamble, in the Camb, 
Nat. Hist., vol. i1., p. 84. 
The three-spined Stickleback, Gasterosteus aculeatus, is a little fish not 
uncommon in the Loch of Loirston, near the village of Cove, Kincardine- 
shire. On visiting this loch towards the end of May 1901, my colleague, 
Dr. H. C. Williamson, found a large proportion of the Sticklebacks infested 
with worms, so much so that many of the little fishes had their abdomens 
distended with the parasites, causing them to assume an abnormal appear- 
ance. Many of the fishes examined had the entire abdominal cavity 
occupied by the parasites. In some cases there was only a single worm of 
large size, folded upon itself two or three times, and which, when 
straightened out, was much longer than the fish. In other cases two, and 
sometimes several, specimens were present, but these were generally of 
smaller size. | 
The loch is frequented by a number of water-birds such as Sea-gulls 
and Terns, and the Heron is also occasionally observed about the loch. 
These birds are liable to be infested with the tape-worm, Schtstocephalus 
solidus, Rudolphi, in its sexually-mature stage, and the Stickleback 
parasite mentioned above is the same worm in its sexually-immature 
condition. 
It is thus evident that some of the birds frequenting the loch had been 
giving shelter to the Schistocephalus, and that larve hatched from the 
* Les Poissons des cotes de Belgique, 87. 
